36 patients with rheumatoid arthritis undergoing total knee arthroplasty were randomized to receive either intra-articular or extra-articular continuous infusion of local anaesthetics. Patients were assessed in terms of patient-controlled analgesia consumption and pain intensity during mobilization. The results demonstrate that patients receiving intra-articular infusion had decreased pain intensity during first exercises compared to the extra-articular infusion group. These findings indicate the potential for improving post-operative mobilization. However, there were no differences in pain relief at rest between the two treatment groups.